There are two commonly used light weight exterior wall panel systems used in the construction industry today, namely aluminum framed curtain walls and exterior insulated finish system (EIFS).
Aluminum framed curtain wall panels are the most common method for providing exterior walls on multi-story buildings, they have extruded dry-seal systems incorporated that protect the building against air and water infiltration and provide superior longevity. A dry seal system can be designed to incorporate the Rain Screen Principle, so the joint can be pressure equalized to help keep moisture away from the seals. The panels can incorporate windows, stone finish or a metal finish. The downside of aluminum framed curtain wall panels is that they perform quite poorly regarding thermal protection of the building.
Exterior insulated panels (sometimes referred to as E.I.F.S.) are becoming more commonly used today for multi-story curtain wall construction. When these panels are properly designed and installed, they will provide optimum thermal protection for a building. Unfortunately, this type of construction typically requires the joints between the panels to be caulked after the panels are erected. Caulking is what is known as a wet-seal system, they are subject to human error and inclement weather. Caulked joints do not provide the same level of quality and endurance as dry-seal systems and incorporating the Rain Screen Principle is difficult to do with caulked joints. Unfortunately caulking the joints needs to be done using scaffolding or swing stages located on the outside of the building, this can be costly and makes the work more dangerous to do. The latter is expensive and adds time required to complete the installation. Caulking is also problematic when the proximity of the adjacent building is too close to the new wall to allow access.
Both of these commonly used systems have disadvantages. In regard to the aluminum framed curtain wall panels it would be advantageous to provide a wall system that has better thermal characteristics. In regard to Exterior Insulated panels (EIFS) it would be advantageous to provide a wall system that incorporates dry seals and reduces onsite work thus reducing the labor costs and inherently increasing the quality of the wall system. It would be further advantageous to provide pressure equalized seal system that also provides a means for moisture to drain from within the seal system.